Guide for broaching tools



Jan. .7, 1930.

V c. c. HANSEN 1,742,765 5 GUIDE FOR BROACHING TOOLS Filed Oct. 4. 1927 v I I I A D Hill III IHI III nun n l illHII IHl1l|| HHH1|HHHHHHIIHHHIIIHHHII 7 I G If 5 '6 Fig-2. 11 FJQ. -11" IN VEN TOR.

may Ganfien BY I 4, III 2.76 HIS ATRNEY l 7 wall suitable guide vention to prevent decllnatlon of the broachtools are used, however, for simultaneously Patented Jan. 7, 1930 GUIDE FOR BROACHIN G TOOLS Application filed October 4, 1927. Serial @No. 223,935.

Figure 1 is a longitudinal side view of a guide constructed in accordance with the practice of the invention,

This invention relates to guides for rock cutting implements, but more particularly to a guide for broaching tools used in fluid actuated rock drills for cutting away the rock between adjacent drill holes.

he present invention is more particularly igure 3 is an elevation of a rock face intended f showing the drill holesand the spacing therewhich two broaching tools are actuated by of Figure 1 on the line he in a horizontal position for making cuts in a vertical rock face. The usual method of removing rock by means of broaching tools is to drill a series of holes in line with the holes so spaced as to leave a wall of material between adjacent holes of a Width which may be readily spanned by the cutting bit of the broaching tool.

rdinarily, where only one broaching tool is being used, the lowermost portion of the of the lower hole may always act as a guide for the tool. ere two broachin our upper holes in PHJIS,

igure 5 is a view similar to Figure 4 showing the succeeding position of the broaching tools and the manner in which the uppermost broaching tool is guided,

igure 6 is an enlarged detail view in elevation of a rock face illustrating the manner in which the lowermost broaching tool is normaily guided by the wall of the drill hole, an

Figure 7 is a similar view illustrating the g manner in which the uppermost broachin oolis held against declination from the debroaching two dividing walls, the upper sired line of cut. broaching tool is preferably provided with a eferring more particularly tothe drawto prevent the cutting bit of ings, A designates a guide comprising a bar the tool from declining from the desired carrying on one side thereof a lateral leg course of out. This is particularly essential O. The bar B is preferably of somewhat in deep cuts where the broach' 7 smaller width than the diameter of the drill of considerable length and due to the loose holesD in the rock E so that wh t of th 1 may drop conlgure 2 is a transverse View taken through 'siderably below the axis of the rock drill rom the broaching cut," a at surface F whereby the broaching tool is actuated. which forms a bearlng for a broaching tool t is t ere or an object of t e present in- G will v lie e axis of the sli htly below th drillhole D. I

The holes are preferably of a'suitable size to receive a bar or other suitable means which may lie across the rock face to preventthe guide Alf the. drill hole beyond the convenient reach abnormalities in the rock formation. of the operator by the broachin tool G and a practical application thereof,

ther ob ects will be in part obvious and in After the horizontal drill hdles D have part pointed out hereinafter; been drilled along a vertica'l line, the ordi- In t e drawingsillustrating the invention nary drill steels may be replaced by the roaching tools G. Inasmuch that the spacspans the wall 1 between the "succeeding pair of drillrholes.

When making broaching cut in the rock, it willbe unnecessary to employ guiding means for either of the broaching tools G since *th broaching tools are satisfactorily supported and guided'by the "wall of the lowermost hole D of each of'the pair of'holes which" the tools Gr span. fter the first'rcut at theuppermost end of theline ofi cuts has been made and the drilling'mechanismvhas been lowered so thatthe' uJppermOst broaching tool Gr spans the wall between the first two pairs of holes D only the lowermost broaching'tool G will be supported'by the wall of the'drill hole. The upper broaching tool G being of substantially the, same width as the slot previously cut and, 'due'to the loose fit of'the tool shank in'the drill chuck as previously mentioned, of saidupper tool G will gradually decline as the tool advances into the rock and, since such declination may reach an extent where the cutting bit will no longer span the width of the wall J, the rock or wall J between the drill holes will be only partly removed. This, however, maybe obviatedby inserting the guide A in thelowermost.of the drill holes D. In this way a substantial bearing surface will be provided I 'for the upper broaching tool G and the guideA will maintain the broaching tool substantiallyin coaxial alignment wit said tool is being actuated.

As will be observed,-the legC is of slif the broaching tool and thusalso thanthe width of the slot between the holes'D, tokenable the guide A to rotate in the drillhole within limits and ,thus' adjust its position with respect'to that of the broachingitool G for which it forms abearing. m

I claim:: c

A, guide adapted to :be i-nsertedliniai d'rill hole for guiding a broaching steel, comprising a bar having edges to engage the wall of a-drill hole atrvpoints remote from 'the surface on the bar forming .a b6t13111f0r the broaching tool, .sai'dbar being offless width than the diameter of the vdrill .hole to enable the flat-surfacetolliezbelowlthe axis of the drillhole, and a leg on'tthelbar adapted to extend into a'precedingbroach- (I cut,- said meansibeing of sufiicientlyiless width than the width of suchbroa'ching cut h the rock drill whereby ficiently less width than'thercutting'bit ofv to enable the bar to be specification.

broaching cut-for supporting thebar a flat adjusted to the most the suitable position by the broaching tool In testimony w CHARLES C. HAN SEN.

ereof I have signed this 

